Protective clothing of many types is now well known for many and varied uses, such as suits for industrial workers, suits for fireman, forest fire fighters, race car drivers and airplane pilots, and suits for use by military personnel, for protection from fire, vapors and harmful substances. Garments include not only complete, hermetic suits, but also individual garments such as trousers, jackets, gloves, boots, hats, head coverings, masks, etc.
Regulations restricting exposure to hazardous environments of various kinds, such as the Occupational Safety and Health Act, make it increasingly necessary to have better and more effective kinds of protective garments. In particular, certain requirements by the U.S. Coast Guard and related requirements by other U.S. government or organizations involve a total protective hermetic suit or envelope around the individual person or fireman. These situations involve cleaning up chemical spills or for fighting chemical fires where the chemical materials are unknown and presumed toxic.
The need for such encapsulating suits for "immediately dangerous to life and health (IDLH)" environments. These suits must be air tight and worn with a self-contained breathing apparatus. (These are termed Level A suits under OSHA/EPA guidelines.) The suit must be nonabsorbent, totally impermeable, and resistant to the widest range of chemicals and reagents in liquid and gaseous forms. It should also be as fire resistant and anti-static as possible. Since these suits are being worn by actively working individuals, they should also be flexible, abrasion resistant, light weight, and should maintain their impermeability while being used.
Such garments presently available are almost invariably of thick construction and heavy in weight, and are often fabricated at least in part from materials impermeable to water or water vapor, such as natural and synthetic rubbers and elastomers, chlorinated rubbers, etc.
Protective clothing comprised of laminates of films have the problem of forming "kinks" when bent so as to restrict movement and become cumbersome. Moreover, some of the protective clothing are porous and provide little protection against hazardous chemical vapors.
Besides the hazards from toxic vapors and fire, being in an atmosphere of highly flammable fumes can present a risk if static charges are generated and build up. Consequently, consideration must be given to provide a protective garment with anti-static properties.
The Gore et al. U.S. Pat. No. 4,194,041 describes a waterproof laminate comprising an outer layer of a hydrophobic material and an inner layer which permits the transfer of moisture vapor. Textile layers can be added for strength and aesthetic characteristics. The textile layers are on the outside of the laminate of the textile layers and the hydrophobic and moisture-vapor permeable layers.
The Falcone U.S. Pat. No. 3,513,057 describes a process for bonding textile fibers to elastomeric ethylene/-higher alpha-olefin copolymers.
The Hansen U.S. Pat. No. 3,809,077 discloses a surgical drape constructed of two layers of thin absorbent compacted webs of randomly interlaced staple textile fibers having disposed therebetween a thin drapable impervious sheet of a thermoplastic film which is adherently bonded to the absorbent sheets across the contacting surfaces thereof by means of a soft latex adhesive.
Ross in U.S. Pat. No. 3,695,967 describes a laminated material having fibrous surfaces made by laminating a nonwoven fibrous layer/thermoplastic film/nonwoven fibrous layer assembly. Lamination of the assembly is accomplished by pressing it with at least one surface which has a multiplicity of closely spaced raised areas while heating the assembly so that at least a portion of the thermoplastic film is raised to a temperature above its softening point.
None of the prior art patents disclose the use of an intermediate fabric which provides anti-static and fire resistant characteristics to the fabric.
Conventional methods of providing an anti-static property to a laminated fabric is to coat the surface with an anti-static agent or to add the anti-static agent into the plastic layer at the time of extrusion. However, surface coatings can be lost by abrasion or by contact with fluids. Furthermore, anti-static agents which are suitable for inclusion into plastics for coextrusion are not fire resistant.